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Modelling the Transport and Biological Effect of Pesticide. Stephen J. Cox. Aims of crop spraying models. Saving money Improving biological control Reducing environmental contamination. Processes involved in spraying. Spray production. Formulation density, viscosity, surface tension
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Modelling the Transport and Biological Effect of Pesticide Stephen J. Cox
Aims of crop spraying models • Saving money • Improving biological control • Reducing environmental contamination
Spray production • Formulation • density, viscosity, surface tension • Droplet size distribution • log normal - 2 parameters • Initial velocities • angles normally distributed from a hydraulic fan nozzle
Transport equations • Ballistic • Random • Combined
Trajectories of 10 droplets 100 mm 300 mm
Capture • Interception • simple collision in space • ‘impaction efficiency’ correction for local airflow deviations • Rebound
Possible improvement • Entrained air and tractor wake • Waving crop • Better rebound model • Speed of calculation
Killing caterpillars • Distribution of pesticide on leaf • Markov chain model of insect behaviour dependent upon degree of poisoning • Simple pharmacokinetics
Further work • More layers in model - perhaps include both sides of leaf • Comparison with experimental data • Integrate with a model of fungal growth to allow efficacy to be investigated